Radiolabelled compounds for diagnosis or treatment of prostate-specific membrane antigen- expressing cancer

A compound, wherein the compound has Formula I or is a salt or a solvate of Formula I:

• wherein:
• each of R1a, R1b and R1c is independently —CO2H, —SO2H, —SO3H, —SO4H, —PO2H, —PO3H, or —PO4H;
• R2 is a linear or branched, cyclic or acyclic, and/or aromatic or non-aromatic C1-C20 alkylenyl or alkenylenyl, or a linear or branched, cyclic or acyclic, and/or aromatic or non-aromatic C2-C20 heteroalkylenyl or heteroalkenylenyl;
• R3 is —O—, —S—, —S(O)—, —S(O)2—, —NHC(O)—, —C(O)NH—,
• R4 is —(CH2)0-3CH(R7)(CH2)0-3—, wherein R7 is (CH2)5CH3,
• each of R5 and R6 is independently hydrogen or methyl;
• Xaa1 is an amino acid of formula —N(R8)R9C(O)—, wherein each R8 is independently hydrogen or methyl, and wherein each R9 is independently:
• a linear or branched, cyclic or acyclic, and/or aromatic or non-aromatic C1-C20 alkylenyl, alkenylenyl, or alkynylenyl;
• or a linear or branched, cyclic or acyclic, and/or aromatic or non-aromatic C2-C20 heteroalkylenyl, heteroalkenylenyl, or heteroalkynylenyl;
• and
• RX is a radiolabeling group independently selected from:
• a radiometal chelator optionally bound by a radiometal;
• an aryl substituted with a radioisotope;
• a prosthetic group containing a trifluoroborate;
• and a prosthetic group containing a silicon-fluorine-acceptor moiety.